BUENOS AIRES (Reuters) - Many delegates from the world’s 20 largest economies arrived at a summit in Argentina this week determined to clinch an agreement to reform the global trade system, pushed to a breaking point by tensions between the United States and China.

To do so, they had to bow to U.S. and Chinese demands to drop some of the pledges that have become hallmarks of the Group of 20 industrialized nations, which represents two-thirds of the global population.